Key-actuated locks

ABSTRACT

The invention provides an improved key actuated lock of the type including a front plate having a keyhole; a bolt with two stumps and two sets of pivoted levers of different lengths for each set provided with stump-receiving slots so that the slots in each set can be aligned by a key to receive a respective stump. The improvement is that the levers and stumps are so arranged that the stump received in the shorter of the sets of levers is masked by the other set of levers when viewed from the front plate thereby making the lock more difficult to pick or drill open.

United States Patent 1 Terry et al.

1 KEY-ACTUATED LOCKS [76] Inventors: Peter Alfred Terry, 35 Halcyon Way, Hornchurch; Ronald Reynolds, 113 Long Green, Chigwell, both of England [22] Filed: Aug. 7, 1973 211 App]. NO.I 386,385

[30] Foreign Application Priority Data July 26, 1973 United Kingdom 37376/72 [52] US. Cl 70/355; 70/353 [51] Int. Cl E05b 21/00 [58] Field of Search 70/353, 354, 355

[56] References Cited UNITED STATES PATENTS 188,962 3/1877 Sargent 70/355 X 840,514 1/1907 Pratorius 70/353 1,568,663 1/1926 Fuber 70/355 1,730,662 10/1929 Kobus 70/355 1,864,429 6/1932 Goroshko et al 70/355 X 51 May 20, 1975 1,935,225 11/1933 Hurd 70/355 FOREIGN PATENTS OR APPLICATIONS 257,695 3/1931 ltaly 70/353 570,211 11/1931 Germany 70/355 Primary Examiner-Roy D. Frazier Assistant ExaminerPeter A. Aschenbrenner Attorney, Agent, or FirmYoung & Thompson [5 7] ABSTRACT The invention provides an improved key actuated lock of the type including a front plate having a keyhole; a bolt with two stumps and two sets of pivoted levers of different lengths for each set provided with stumpreceiving slots so that the slots in each set can be aligned by a key to receive a respective stump. The improvement is that the levers and stumps are so arranged that the stump received in the shorter of the sets of levers is masked by the other set of levers when viewed from the front plate thereby making the lock more difficult to pick or drill open.

9 Claims, 5 Drawing Figures PATH-HEB :mzmws 3, 884, 058

srm 1 OF 3 PATENTED "M20195 3.884.058

SHEET 2 OF 3 AT [9T 5 MYZOIBYS sum 3 or a KEY-ACTUATEDILOCKS This invention relates to key-actuated locks, and aims at the provision of a lock providing'greater security against access to interior components of the lock, than has been providediri previously known locks.

The invention consists in a key-actuated lock incorporating a bolt and pivoted levers'rockable by a correct key in order to bring slots in the levers into positions allowing withdrawal of the bolt to release the lock, wherein the lever assembly incorporates levers of two different lengths.

The lever assembly may comprise a plurality of levers of longer length, and a plurality of levers of shorter length rockable about a common pivot. The bolt is provided with two stumps cooperating respectively with the longer and the shorter lever(s) to prevent withdrawal of the bolt unless and until the levers are rocked by the key to prearranged angular positions; and having regard to the lengths of the longer and shorter levers these stumps are located at different positions longitudinally of the bolt. When the lock is, assembled the stump cooperating with the shorter lever(s) is then masked by the longer lever(s) of the assembly. Preferably the levers and bolt are actuable by a double-bitted key.

The invention will be clearly understood from the following description of one form (given, however, merely by way of example) which it may assume, and this description will be more readily followed by reference to the accompanying drawings wherein FIG. 1 represents in perspective the components of a lock in accordance with the invention in exploded positions:

FIG. 2 represents in side elevation the parts shown in FIG. 1 when assembled:

FIGS. 3 and 4 represent face views of the assembly shown in FIG. 2, respectively in the planes A-A and B-B of FIG. 2: and

FIG. 5 represents a view corresponding to FIG. 4 after the lock has been actuated by the key and the bolt withdrawn.

In carrying the invention into effect in one convenient manner, as shown in the aforesaid drawings, a key-actuable lock comprises a bolt, and a plurality of pivoted levers held in assembly between a backplate 1 and a front plate 2, which are, when assembled, held together in spaced positions by posts 3. A bolt 4 has a tailplate 5 and is slidable between the upper and lower pairs of posts 3. A pin 6 upstanding from the backplate l engages in a slot 7 of the tailplate 5. The tailplate 5 is also provided with an aperture 8 for engagement by a key, to displace the bolt when turned.

A plurality of plate levers in face-to-face assembly is pivoted by holes 9 on the pin 6 constituting a common pivot for all the levers. Each lever is fitted with a strip spring 10 to bear against a flattened surface of an upper or lower post 3 in order to bias the levers in one or other sense about their pivot. Each lever has also an aperture 11 to cooperate with a tooth of a key 12 (FIG. 2) inserted through a keyhole 13 in the front plate 2 and turned about a pin 14 on to which the hollow stem of the key slides. Each lever in addition has in its edge remote from the pivot 6 a radial slot in a selected angular position. The slot positions and the shapes of the apertures 11 are so chosen that when the correct key enters the apertures 11 and is turned, the levers each rocked about its pivot by its respective tooth of the key, assume positions in which slots are aligned with one another and with stump means on the bolt,-so that the stump means can enter the slots as the bolt is withdrawn by the key. If an incorrect key is used the lever slotsare not properly aligned, and one or more levers obstructing bolt stump means prevents withdrawal of the bolt.

A lock as so far described above conforms substantially with known key-actuated lever locks. However, in accordance with the invention a lock as described above incorporates levers of different radial lengths extending from their common pivotal axis.

In the eight-lever form of lock illustrated there are incorporated a group of four levers 15 of shorter radial length, and another group of four levers 16 of longer radial length. All the shorter levers 15 are grouped 'face-to-face, and the group located adjacent to the backplate 1, while the group of longer levers, also faceto-face with one another is mounted in front of the group of shorter levers, with reference to the backplate 1.

Separate stump means are provided on the bolt to cooperate respectively with the shorter and the longer levers and may comprise an upstanding stump 17 suitably located on the tailplate 5 of the bolt to cooperate with the shorter levers (FIG. 3), and a stump 18 extending rearwards from the bolthead 4, and upstanding from the tailplate 5, to cooperate with the longer levers. In other words the arrangement is such that when operated by a correct key the levers 15 more to align their slots with one another and with the stump 17, while the levers 16 move to align their slots with one another and with the stump 18, so that the key can retract the bolt (FIG. 5). It will be seen that the stump 17 is screened by the outer, longer levers 16, so that any attempt to bore through the front plate 2 in order to gain access to the stump 17 for removal, is frustrated.

As seen in FIG. 1 the edge of the stump 18 may be recessed to form a tongue 19 adapted to engage a stepped slot 20 in the outermost lever 16 (FIG. 5), in order to retain the bolt in withdrawn position when the lock is released by key. As illustrated the facing edges of the stump 18 and the longer levers 16 may be toothed or serrated to prevent relative sliding movement when in contact. The edges of the shorter levers 15 may, as shown, be likewise serrated. It is preferred that a lock such as described above shall be actuated by a double-bitted key (FIG. 2), but the invention is not limited in this respect.

From the above description it will be seen that the invention provides a lock of improved security, but it should be understood that the invention is not limited solely to the details of the form described above which may be modified in various ways in order to meet requirements and conditions encountered, without departing from the scope of the invention.

What we claim is:

1. In a key-actuated lock including: a front plate having a keyhole; a bolt; two stumps spaced apart on said bolt; a first set of pivoted levers, each of the same length and provided with a stump-receiving slot; and a second set of pivoted levers, each of the same length, which is shorter than the length of the first set of levers, and provided with a stumpreceiving slot, the sets of levers being rockable by a correct key located through the said keyhole to align the said slots of the first set of levers to receive one of the said stumps and simultaneously to align the said slots of the second set of levers to receive the other of the stumps whereby the bolt can be withdrawn to release the lock, the improvement consisting in that the stump received in the slots of the second set of levers is masked by the first set of levers when viewed from the front plate.

2. A lock as claimed in claim 1 wherein the two sets of levers are rockable about a common pivot.

3. A lock as claimed in claim 1 wherein each set of levers consists of a plurality of levers.

4. A lock as claimed in claim 1 comprising a lever having an inwardly stepped slot for engagement by the cooperating bolt stump.

5. A lock as claimed in claim 1 comprising levers with irregular edges facing the cooperating stump.

6. A lock as claimed in claim 5 wherein the surface of the said stump facing said irregular edges, is likewise irregular.

7. A lock as claimed in claim 5 wherein the levers have serrated edges facing the cooperating stump.

8. A lock as claimed in claim 7 wherein the said cooperating stump has a toothed surface facing said lever edge.

9. A lock as claimed in claim 1 wherein the levers are so apertured to cooperate with a key that the lock requires a double-bitted key for actuation. 

1. In a key-actuated lock including: a front plate having a keyhole; a bolt; two stumps spaced apart on said bolt; a first set of pivoted levers, each of the same length and provided with a stump-receiving slot; and a second set of pivoted levers, each of the same length, which is shorter than the length of the first set of levers, and provided with a stumpreceiving slot, the sets of levers being rockable by a correct key located through the said keyhole to align the said slots of the first set of levErs to receive one of the said stumps and simultaneously to align the said slots of the second set of levers to receive the other of the stumps whereby the bolt can be withdrawn to release the lock, the improvement consisting in that the stump received in the slots of the second set of levers is masked by the first set of levers when viewed from the front plate.
 2. A lock as claimed in claim 1 wherein the two sets of levers are rockable about a common pivot.
 3. A lock as claimed in claim 1 wherein each set of levers consists of a plurality of levers.
 4. A lock as claimed in claim 1 comprising a lever having an inwardly stepped slot for engagement by the cooperating bolt stump.
 5. A lock as claimed in claim 1 comprising levers with irregular edges facing the cooperating stump.
 6. A lock as claimed in claim 5 wherein the surface of the said stump facing said irregular edges, is likewise irregular.
 7. A lock as claimed in claim 5 wherein the levers have serrated edges facing the cooperating stump.
 8. A lock as claimed in claim 7 wherein the said cooperating stump has a toothed surface facing said lever edge.
 9. A lock as claimed in claim 1 wherein the levers are so apertured to cooperate with a key that the lock requires a double-bitted key for actuation. 